C550XL BK
C551XL BK x2
These are "compatible" cartridges, not Canon's own. The Canon website suggests that they will fit a number of Pixma printers. This website has the list:
https://store.canon.co.uk/canon-cli-551xl-high-yield-black-ink-cartridge/64...
Please let me know when you'd like to collect.
Thanks,
Steve